The explicit solution method is a true dynamic procedure originally developed to model high-speed impact events in which inertia plays a dominant role in the solution. Out-of-balance forces are propagated as stress waves between neighboring elements while solving for a state of dynamic equilibrium. Since the minimum stable time increment is usually quite small, most problems require a large number of increments.

The explicit solution method has proven valuable in solving static problems as well—ABAQUS/Explicit solves certain types of static problems more readily than ABAQUS/Standard does. One advantage of the explicit procedure over the implicit procedure is the greater ease with which it resolves complicated contact problems. In addition, as models become very large, the explicit procedure requires less system resources than the implicit procedure. Refer to Chapter 3, “Overview of Explicit Dynamics,” for a detailed comparison of the implicit and explicit procedures.

Applying the explicit dynamic procedure to quasi-static problems requires some special considerations. Since a static solution is, by definition, a long-time solution, it is often computationally impractical to analyze the simulation in its natural time scale, which would require an excessive number of small time increments. To obtain an economical solution, the event must be accelerated in some way. The problem is that as the event is accelerated, the state of static equilibrium evolves into a state of dynamic equilibrium in which inertial forces become more dominant. The goal is to model the process in the shortest time period in which inertial forces remain insignificant.